Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F297/00—Macromolecular compounds obtained by successively polymerising different monomer systems using a catalyst of the ionic or coordination type without deactivating the intermediate polymer
  • C08F297/06—Macromolecular compounds obtained by successively polymerising different monomer systems using a catalyst of the ionic or coordination type without deactivating the intermediate polymer using a catalyst of the coordination type
  • C08F297/08—Macromolecular compounds obtained by successively polymerising different monomer systems using a catalyst of the ionic or coordination type without deactivating the intermediate polymer using a catalyst of the coordination type polymerising mono-olefins
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F10/00—Homopolymers and copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F10/00—Homopolymers and copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond
  • C08F10/04—Monomers containing three or four carbon atoms
  • C08F10/06—Propene
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F4/00—Polymerisation catalysts
  • C08F4/42—Metals; Metal hydrides; Metallo-organic compounds; Use thereof as catalyst precursors
  • C08F4/44—Metals; Metal hydrides; Metallo-organic compounds; Use thereof as catalyst precursors selected from light metals, zinc, cadmium, mercury, copper, silver, gold, boron, gallium, indium, thallium, rare earths or actinides
  • C08F4/60—Metals; Metal hydrides; Metallo-organic compounds; Use thereof as catalyst precursors selected from light metals, zinc, cadmium, mercury, copper, silver, gold, boron, gallium, indium, thallium, rare earths or actinides together with refractory metals, iron group metals, platinum group metals, manganese, rhenium technetium or compounds thereof
  • C08F4/62—Refractory metals or compounds thereof
  • C08F4/64—Titanium, zirconium, hafnium or compounds thereof
  • C08F4/642—Component covered by group C08F4/64 with an organo-aluminium compound
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F110/00—Homopolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond
  • C08F110/04—Monomers containing three or four carbon atoms
  • C08F110/06—Propene
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F2410/00—Features related to the catalyst preparation, the catalyst use or to the deactivation of the catalyst
  • C08F2410/05—Transitioning, i.e. transition from one catalyst to another with use of a deactivating agent
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F4/00—Polymerisation catalysts
  • C08F4/42—Metals; Metal hydrides; Metallo-organic compounds; Use thereof as catalyst precursors
  • C08F4/44—Metals; Metal hydrides; Metallo-organic compounds; Use thereof as catalyst precursors selected from light metals, zinc, cadmium, mercury, copper, silver, gold, boron, gallium, indium, thallium, rare earths or actinides
  • C08F4/60—Metals; Metal hydrides; Metallo-organic compounds; Use thereof as catalyst precursors selected from light metals, zinc, cadmium, mercury, copper, silver, gold, boron, gallium, indium, thallium, rare earths or actinides together with refractory metals, iron group metals, platinum group metals, manganese, rhenium technetium or compounds thereof
  • C08F4/62—Refractory metals or compounds thereof
  • C08F4/64—Titanium, zirconium, hafnium or compounds thereof
  • C08F4/659—Component covered by group C08F4/64 containing a transition metal-carbon bond
  • C08F4/65912—Component covered by group C08F4/64 containing a transition metal-carbon bond in combination with an organoaluminium compound

Definitions

• R is hydrogen or an alkyl, cycloalkyl or aryl radical with 1-10 car ⁇ bon atoms
• one or more of the said olefins are polymerized in the presence of a catalyst comprising the product of the reaction of an alkyl-Al compound with a compound of Ti and/or V supported on a magnesium halide in active form, obtaining an olefin polymer.
• Multistage processes for the polymerization of olefins, carried out in two or more reactors are known from the patent literature and are of particular interest in industrial practi ⁇ ce.
• process parameters such as temperature, pressure, type and con ⁇ centration of monomers, concentration of hydrogen or other mole ⁇ cular weight regulator, provides much greater flexibility in controlling the composition and properties of the end product with single-stage processes.
• Multistage processes are generally carried out using the same catalyst in the various stages/reactors: the product obtained in one reactor is discharged and sent directly to the next stage/reactor without altering the nature of the catalyst.
• Processes in several stages find application for example in the preparation of olefin (co)polymers with broad molecular weight distribution (MWD) , by producing polymer species with different molecular weight in the various reactors.
• the molecu ⁇ lar weight in each reactor, and therefore the range of the MWD of the final product, is generally controlled by using different concentrations of a molecular weight regulator, which is prefe ⁇ rably hydrogen.
• Multistage processes are also used in the prepa ⁇ ration of high-impact propylene copolymers by sequential polyme ⁇ rization of propylene and mixtures of propylene with ethylene.
• propylene is homopolymerized or copolymerized with smaller proportions of ethylene and/or olefins having 4-10 carbon atoms, obtaining a stereoregular polymer; in a second stage, mixtures of ethylene and propylene are polymerized in the presence of the polymer including the catalyst that is obtained in the first stage, obtaining polypropylene compositions having improved impact strength.
• European Patent Application EP-A-433989 describes a process for preparing polypropylene composition containing from 20 to 99% by weight of a crystalline (co)polymer, containing at least 95% by weight of propylene units, and from 1 to 80% by weight of a noncrystalline ethylene/propylene copolymer, containing from 20 to 90% by weight of ethylene units.
• the process is carried out in 2 stages: in a first stage, carried out in liquid prop ⁇ ylene, the crystalline propylene (co)polymer is produced, and in a second stage, carried out in hydrocarbon solvent, the non- crystalline ethylene/propylene copolymer is produced.
• the same catalyst consisting of a chiral metallocene and an aluminoxane, is used in both stages.
• European Patent Application EP-A-433990 describes a process in two stages for the preparation of propylene-based polymer composition similar to those described in EP-A-433989, in which the crystalline propylene (co)polymer is produced in the first stage by polymerization in liquid propylene, and the noncrystal ⁇ line ethylene/propylene copolymer is produced in the second sta ⁇ ge by gas-phase polymerization. Also in this case, the same ca ⁇ talyst, consisting of a chiral metallocene and an aluminoxane is used in both reactors.
• German Patent Application DE 4130429 describes a multistage process for the production of block copolymers, effected enti ⁇ rely in the gas phase.
• a first stage there is production of a matrix consisting of a homo or copolymer of propylene in a quan ⁇ tity of between 45 and 95% by weight based on the total product;
• a second stage carried out in the presence of the polypropylene matrix previously produced and of the catalyst used therein, an ethylene/ ⁇ -olefin copolymer is prepared, con ⁇ taining from 0.1 to 79.9% by weight of ethylene units, in a quantity of between 5 and 55% by weight based on the total pro ⁇ duct.
• the process of the invention comprises a first stage in which, in the presence of titanium catalysts or vana ⁇ dium catalysts, an olefinic polymer is prepared, and a second stage in which the catalyst used in the first stage is deactiva ⁇ ted, and a third stage in which, in the presence of the said olefin polymer and of a compound of a transition metal M sele ⁇ cted from Ti, Zr, V, or Hf containing at least one M- ⁇ bond an ⁇ d/or of their reaction products, one or more olefins are polyme ⁇ rized, said olefins being equal to or different from those pol ⁇ ymerized in the first stage.
• the olefin homo- or copolymer produced in the first stage of polymerization (A) has porosity, expressed as percentage of voids, greater than 5%, preferably greater than 10%, more preferably greater than 15%.
• the polymers produced in the first stage of polymerization (A) are characterized by the fact that they have macroporosity. In general, more than 40% of the porosity of the said polymers is due to pores with diameter greater than 10000 A.
• the porosity expressed as percentage of voids, and the distribution of pore radius are determined by the mercury method described hereinafter.
• the amount of polymer produced in the first stage of polymerization (A) is generally greater than 1000 g/g of solid component, preferably greater than 2000 g/g, more preferably greater than 3000 g/g.
• the amount of polymer produced in polymerization stage (A) is preferably between 10 and 90% by weight relative to the total amount of polymer produced in stages (A) and (C) and more prefe ⁇ rably is between 20 and 80%.
• a solid component comprising a compound of a transition metal M 1 selected from Ti and V and not containing M l - ⁇ bonds, supported on a magnesium halide in active form.
• the solid component can also comprise an electron-donor compound (internal donor).
• an electron-donor compound internal donor
• the internal donor is used when the solid component is used for preparing catalysts for the stereospecific polymerization of propylene, 1-butene and similar ⁇ -olefins, where a high stereospecificity is necessary to obtain polymers with an isotactic index higher than 90;
• an alkyl-Al compound and optionally an electron-donor com ⁇ pound (external donor) .
• stereoregular polymers are produced in the first stage of polymerization (I) , for example polymers of propylene with high isotacticity index
• the external donor is used for impar ⁇ ting the necessary stereospecificity to the catalyst.
• diethers of the type described in Patent EP-A-361493 are used as internal donors, the stereospecificity of the catalyst is sufficiently high in itself and the external donor is not necessary.
• TiCl TiCl 3 and the halogen-alcoholates of formula Ti(OR I ) m X n in which R 1 is a hydrocarbon radical with 1-12 carbon atoms or a -COR 1 group, X is a halogen and (m+n) is the valence of titanium.
• the catalytic component (i) is advantageously used in the form of spherical particles with mean diameter between about 10 and 150 ⁇ m.
• Suitable methods for the preparation of said compo ⁇ nents in spherical form are described for example in Patents EP-A-395083, EP-A-553805, EP- A-553806, whose description rela ⁇ ting to the method of preparation and to the characteristics of the products is herein incorporated for reference.
• Examples of internal donor compounds are ethers, esters, in particular esters of polycarboxylic acids, amines, ketones and 1,3-diethers of the type described in Patents EP-A-361493, EP-A- 361494, EP-A-362705 and EP-A-451645.
• the alkyl-Al compound (ii) is generally selected from the trialkyl aluminium compounds such as for example triethyl-Al, triisobutyl-Al, tri-n-butyl-Al, tri-n-hexyl-Al, tri-n-octyl-Al. It is also possible to use mixtures of trialkyl-Al's with alkyl- Al halides, alkyl-Al hydrides or alkyl-Al sesquichlorides such as AlEt 2 Cl and Al 2 Et 3 Cl 3 .
• the external donor can be the same as or can be different from the internal donor.
• the internal donor is an ester of a polycarboxylic acid, such as a phthalate
• the external donor is preferably selected from silicon compounds of formula R j ⁇ Si- (OR) 2 , where R x and R are alkyl, cycloalkyl or aryl radicals with 1-18 carbon atoms.
• Examples of such silanes are methylcyclohexyldimethoxysilane, diphenyldimethoxysilane, methyl-t-butyldimethoxysilane, dicyclopentyldimethoxysilane.
• the compounds of the transition metal M used in treatment stage (b) are selected from the compounds of Ti, V, Zr and Hf containing at least one M- ⁇ bond.
• said compounds contain at least one ligand L, having a mono- or polycyclic structure containing conjugated ⁇ electrons, coordinated on the metal M.
• Said compound of Ti, V, Zr or Hf is preferably selected from components having the following structure: Cp I MR 1 a R 2 b R 3 c (I) Cp I Cp II MR 1 a R 2 b (II) (Cp I -A ⁇ -Cp II )MR 1 a R 2 b (III) in which M is Ti, V, Zr or Hf; Cp 1 and Cp 11 , equal or different, are cyclopentadienyl groups, or substituted cyclopentadienyl groups; two or more substituents on said cyclopentadienyl groups can form one or more rings having from 4 to 6 carbon atoms; R 1 , R 2 and R 3 , equal or different, are atoms of hydrogen, halogen, an alkyl or alkoxy group with 1-20 carbon atoms, aryl, alkylaryl or arylalkyl with 6-20 carbon atoms, an acyloxy group with 1-20 carbon atom
• Representative compounds having formula (I) comprise: (Me 5 Cp)MMe 3 , (Me 5 Cp)M(OMe) 3 , (Me 5 Cp)MCl 3 , (Cp)MCl 3 , (Cp)MMe 3 , (MeCp)MMe 3 , (Me 3 Cp)MMe 3 , (Me 4 Cp)MCl 3 , (Ind)MBenz 3 , (H 4 Ind)MBenz 3 , (Cp)MBu 3 .
• Representative compounds having formula (II) comprise: (Cp) 2 MMe 2 , (Cp) 2 MPh 2 , (Cp) 2 MEt 2 , (Cp) 2 MCl 2 , (Cp) 2 M(OMe) 2 , (Cp) 2 M(OMe)Cl, (MeCp) 2 MCl 2 , (Me 5 Cp) 2 MC1 2 , (Me 5 Cp) 2 MMe 2 , (Me 5 Cp) 2 MMeCl, (Cp) (Me 5 Cp)MCl 2 , (l-MeFlu) 2 MCl 2 , (BuCp) 2 MCl 2 , (Me 3 Cp) 2 MC1 2 , (Me 4 Cp) 2 MCl 2 , (Me 5 Cp) 2 M(OMe) 2 , (Me 5 Cp) 2 M(OH)Cl, (Me 5 Cp) 2 M(OH) 2 , (Me
• Representative compounds of formula (III) comprise: C 2 H 4 (Ind) 2 MCl 2 , C 2 H 4 (Ind) 2 MMe 2 , C 2 H 4 (H 4 Ind) 2 MC1 2 , C 2 H 4 (H 4 Ind) 2 MMe 2 , Me 2 Si(Me 4 Cp) 2 MCl 2 , Me 2 Si(Me 4 Cp) 2 MMe 2 , Me 2 SiCp 2 MCl 2 , Me 2 SiCp 2 MMe 2 , Me 2 Si(Me 4 Cp) 2 MMeOMe, Me 2 Si(Flu) 2 MCl 2 , Me 2 Si (2-Et-5-iPrCp) 2 MCl 2 , Me 2 Si(H 4 Ind) 2 MCl 2 , Me 2 Si(H 4 Flu) 2 MC1 2 , Me 2 SiCH 2 (Ind) 2 MCl 2 , Me 2 Si(2- Me- H 4 Ind) 2 MCl 2 , Me 2 Si
• the first stage of polymerization (A) can be carried out in liquid phase or in gas phase, working in one or more reactors.
• Gas-phase polymerization can be carried out using the known fluidized-bed technique or working in conditions in which the bed is mechanically stirred.
• the treatment stage (B) is carried out advantageously in two parts, (a) first bringing into contact the polymer produced in polymerization stage (A) with compounds that are able to dea ⁇ ctivate the catalyst used in said stage (A) , and then (b) , brin ⁇ ging into contact the product obtained in (a) with solutions of the transition metal M in hydrocarbon solvents (benzene, tolue ⁇ ne, heptane, hexane, liquid propane and the like) .
• hydrocarbon solvents benzene, tolue ⁇ ne, heptane, hexane, liquid propane and the like
• Examples of compounds that can be used in treatment stage (a) can be selected from the group consisting of compounds ha ⁇ ving the general formula R y . j XH in which R is hydrogen or a hydrocarbon group with from 1 to 10 carbon atoms, X is 0, N, or S, and y is the valency of X.
• Non-limitative examples of such compounds are represented by alcohols, thioalcohols, mono- and di-alkylamines, NH 3 , H 2 0 and H 2 S.
• Preferred compounds are those in which X is 0 and among these, a particularly preferred compound is water.
• treatment stage (a) Other examples of compounds that can be used in treatment stage (a) are CO, COS, CS 2 , C0 , 0 and acetylenic or allenic compounds.
• the molar ratio between the deactivating compound and the compound of the transition metal M 1 should preferably be such as to ensure substantial deactivation of the catalyst of stage (A) .
• the value of this ratio is preferably greater than 50, more pre ⁇ ferably greater than 150 and in particular greater than 250.
• Treatment (a) in which these deactivating compounds are brought into contact with the polymer produced in stage (A) , can be effected in various ways.
• the polymer is brought into contact, for a time ranging from 1 minute to some hours, with a hydrocarbon solvent that contains the deactivating compound in solution, suspension or dispersion.
• a hydrocarbon solvent that contains the deactivating compound in solution, suspension or dispersion.
• An example of dispersion of the deactivating compound in a hydrocarbon solvent is represented by humidified hexane.
• the liquid is removed and the polymer undergoes treatment (b) .
• the said treatment (b) can be carried out by suspending the polymer obtained from stage (a) in hydrocarbon solvents containing the dissolved compound of transition metal M, and optionally an alkyl-Al compound and/or an aluminoxane, generally working at temperature between 0 and 100°C, preferably between 10 and 60°C, and removing the solvent at the end of the treatment.
• the polymer obtained from (a) can be brought into contact, dry, with solutions of the compound of the transition metal M containing the minimum quan ⁇ tity of solvent for keeping the said compound in solution.
• Stage (B) can be conveniently carried out in the gas phase in a loop reactor, in which the polymer produced in the first stage of polymerization is circulated by a stream of inert gas.
• Solutions of the deactivating compound and of the compound of the transi ⁇ tion metal M are fed successively, for example using a sprayer, to the loop reactor in the gas phase, and a free-flowing product is obtained at the end of the treatment.
• the product is treated with compounds that are able to decontaminate the system, for example with alkyl-Al compounds.
• the quantity of compound of the transition metal M, expressed as metal, contained in the product obtained from stage (B) can vary over a wide range depending on the compound of transition metal M used and on the relative quantity of product that it is desired to produce in the various stages. Generally this quantity is between 1-10 "7 and 5-10 -3 g of metal M/g of pro ⁇ duct, preferably between 5-10 "7 and 5*10" 4 , more preferably be ⁇ tween 1*10" 6 and 1-10 "4 .
• an alkyl-Al compound selected from Al-trialkyls in which the alkyl groups have 1-12 carbon atoms, and linear or cyclic aluminoxane compounds containing the repeat unit -(R 4 )Al ⁇ - in which R 4 is an alkyl group with 1-12 carbon atoms or a cycloalkyl or aryl group with 6-10 carbon atoms, the said aluminoxane compounds containing from 1 to 50 repeat units.
• the alkyl-Al compound is fed to polymerization stage (C) when treatment (b) in stage (B) is carried out in the absen ⁇ ce of alkyl-Al compounds.
• Treatment stage (B) in fact makes it possible to work with different catalytic systems in polymerization stages (A) and (C) .
• the process of the invention can be used for preparing a wide range of olefin polymer compositions.
• the process of the invention is particularly suitable for the pro- duction of high-impact polypropylene (heterophase copolymers of propylene) .
• high-impact polypropylene heterophase copolymers of propylene
• a further aspect of the present invention is a process for the preparation of heterophase copolymers of propylene, characterized in that it comprises:
• Non-limitative examples of substantially amorphous olefin (co)polymers that can be prepared in stage (C) are the elastomeric copolymers of ethylene and propylene and the elastomeric terpolymers of ethylene and propylene with smaller proportions of a diene, which have a content by weight of units derived from ethylene between about 30 and 70%; the elastomeric copolymers of ethylene and butene and the elastomeric terpolymers of ethylene, butene and propylene having a content by weight of units derived from ethylene between about 30 and 70%; the atactic polypropylenes with high molecular weight ( ⁇ > 1) .
• Polymerization stage (A) can be conveniently carried out in liquid propylene, working in one or more loop reactors, or in the gas phase, working in one or more reactors with fluidized bed or mechanically stirred bed.
• the gas-phase technology with a fluidized-bed is preferred.
• the porosity (expressed as percentage of voids) of the pol ⁇ ymer produced in the first stage of polymerization (A) is prefe ⁇ rably greater than 15% and more preferably greater than 20%.
• the distribution of pore radius is such that more than 40% of the porosity is due to pores with diameter greater than 10000 A.
• more than 90% of the porosity is due to pores with diameter greater than 10000 A.
• the amount of polymer produced in polymerization stage (C) is preferably between 25% and 75%, more preferably between 35% and 65% by weight based on the total amount of polymer produced in stages (A) and (C) .
• the process is preferably carried out continuously, working in both stages of polymerization (A) and (C) in gas-phase fluidized-bed reactors and effecting stage (B) in a gas-phase loop reactor.
• Porositv fine] smrface with nitrogen are determined according to B.E.T. methodology (equipment used: SORPTOMATIC 1800 from Carlo Erba) .
• Size of catalyst particles is determined by a method based on the principle of optical diffraction of monochromatic laser light with the "Malvern Instr. 2600" apparatus. The mean size is stated as P50.
• Melt Index E (MIE) : determined according to ASTM-D 1238, method E.
• Ratio of degrees fF/E ratio of Melt Index F to Melt In ⁇ dex E.
• Porosity the porosity expressed as percentage of voids is determined by absorption of mercury under pressure. The volume of mercury absorbed corresponds to the volume of the pores.
• a calibrated dilatometer (diameter 3 mm) CD3 (Carlo Erba) connected to a reservoir of mercury and to a high-vacuum pump (1-10 -2 mba) is used. A weighed amount of sample (about 0.5 g) is placed in the dilatometer. The apparatus is then placed under high vacuum ( ⁇ 0.1 mm Hg) and is kept in these conditions for 10 minu ⁇ tes.
• Stage (B) Treatment (a) with H 0 and treatment fb) with EBTHI-

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